Louisville Water deploys robotic crawler for condition assessment

Louisville Water Tower and Pumping Station house the WaterWorks Museum

To many history buffs, “the prettiest ornamental water tower and pumping station” in the U.S. belongs to Louisville Water Company (Louisville Water). In 1860, the water company, which today provides water to more than 850,000 people in Louisville, Kentucky and surrounding communities, built its first water tower and pumping station in the form of a Greek temple complex.

Today, the Louisville Water Tower and Pumping Station house the WaterWorks Museum, and Louisville Water continues to make history using modern technology from Pure Technologies to assess its extensive water network.

Focused on pipes with the potential to cause the most damage

Following a water main break in 2009 that resulted in the loss of 15 million gallons of treated water, Louisville Water began a Transmission Assessment Program, first deploying Pure’s PipeDiver® technology to conduct a practical and cost-effective way to inspect transmission mains. Over the succeeding years, this program has evolved to include with other assessment technologies from Pure’s toolbox.

Transmission Assessment Program utilizes a variety of assessment tools

In the summer of 2015, Louisville Water deployed PureRobotics to assess 3.41 miles of 24 to 30-inch transmission mains in its network. With over 4,100 miles of pipeline to maintain (200 miles of it transmission main), Louisville Water focused its condition assessment on its transmission main system – pipes that would cause the greatest amount of damage in the case of failure. The loss of non-revenue water, either in continuing small amounts or from a catastrophic failure, can result in massive costs to a water utility.

By prioritizing the risk levels associated with their transmission main system, Louisville Water has created an ongoing inspection program to keep a watchful eye on the health of their pipelines. The program utilizes a number of Pure Technologies assessment tools to find active leaks as well as potential future threats.

In May of 2015, PureRobotics was deployed on the Cross County Header, Ray Lane Easement pipeline, and Bardstown Road pipelines. For Louisville Water, PureRobotics used CCTV to provide a comprehensive high-definition visual inspection. The robotic crawler was also outfitted with specialized tools to conduct an electromagnetic assessment on the condition of the pipeline and inertial measurement unit (IMU) for a GIS component.

The Inertial Measurement Unit (IMU) deployed with PureRobotics uses a series of Fiber Optic Gyroscopes (FOGs) and accelerometers to track depth, lateral and horizontal movements from a known GPS reference point. The output is a GIS spatial map of the pipeline which depicts elevation changes as well as notable features of interest encountered during the inspection.

PureEM electromagnetic assessment detects anomalous regions in the pipe cylinder and prestressed wires. This data is correlated with odometer readings from the PureRobotics umbilical tether as well as HD recorded CCTV and IMU to attempt to locate areas of distress in the pipeline.

Anomalous pipe

One of the 11 anomalous pipes excavated.

Due to its mobility, PureRobotics is ideal for multiple isolated inspection runs where a quick setup and breakdown can improve efficiency.  The transporter can be deployed from a number of access styles including valves, open flange, and open pipe. In the case of the Louisville Water inspection, the PureRobotics system was inserted into the pipeline via newly installed vertical gate valves and existing boiler plate style hatches. Inspection lengths varied in length from 70 feet to beyond 2,000 feet.

Staff deploying PureRobotics

Louisville Water deployed PureRobotics to assess its transmission mains.

Results gave Louisville Water the confidence to prioritize its rehabilitation program

High definition CCTV inspection results showed a number of longitudinal cracks consistent with overloading. These types of mortar cracks may eventually lead to corrosion of the steel cylinder or prestressing wire and eventually a failure of the pipe.

One pipe section in the Ray Lane Easement pipeline was found to display anomalous electromagnetic signals showing a significant number of broken prestressing wire wrap breaks as well as cylinder wall loss. This was correlated with visual data, showing spalling and exposed steel at the invert of the pipe.

Visual assessment also showed a number of pipe sections with spalling. Electromagnetic assessment also found 11 pipes with anomalous signals not consistent with wire breaks. Investigation performed on one of these anomalous pipes showed a non-standard metal sleeve used in manufacturing. From this information, it was determined that the remaining 10 anomalous pipes could be left in service.

As one of the first utilities to deploy the third generation PureRobotics platform, Louisville Water now has defensible data to move forward with its ongoing rehabilitation program. For this historic water utility, modern technology really can help.